Group Andreas Feigenspan


Cellular Physiology of the Retina


Nerve cells are modular information processing units, which are integrated into larger neuronal networks. Whereas the functioning of any such network is largely dependent on the synaptic communication between its constituents, the properties of individual neurons are equally important. These properties are defined by the functional morphology of neurons, meaning a unique combination of size, shape and expression of signal transduction proteins.


The neuronal network of the mammalian retina deconstructs images from the outside world into salient features like contrast, luminosity and color, and it processes this information simultaneously in multiple parallel pathways. Therefore, a large amount of visual processing already takes place in the retina, but its underlying principles are far from being clear.

We are interested in how these parallel pathways are implemented in neuronal circuits, and how they contribute to the overall processing of visual information. Therefore, we analyze the morphological and physiological properties of different classes of retinal neurons in order to understand their particular function within the network. Experiments are carried out on the level of individual cells, and they are subsequently extended to the analysis of microcircuits. For example, we investigate how the flow of information in vertical pathways from photoreceptors to ganglion cells is influenced by lateral interactions from horizontal cells and amacrine cells.

Since injury to the optic nerve is a common cause of blindness, our research also focuses on the physiology of regenerating axons and growth cones. A profound understanding of these structures is a prerequisite for generating permissive environments necessary for successful axonal regrowth.


Immunocytochemical techniques in combination with three-dimensional reconstruction algorithms are used to investigate the morphology and circuitry of retinal neurons. In addition, we implement modern electrophysiological approaches such as patch-clamp as well as intra- and extracellular recordings, which are combined with imaging techniques based on multi-photon laser-scanning microscopy.